[cfe] Report errors on restricted instance members in enums

Part of #47453

Change-Id: I2fddd2ad5da82807fef7e9ed1d7a6781fde38600
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/237365
Reviewed-by: Johnni Winther <[email protected]>
Commit-Queue: Chloe Stefantsova <[email protected]>

Author: chloestefantsova

pkg/_fe_analyzer_shared/lib/src/messages/codes_generated.dart

@@ -2777,15 +2777,39 @@ const MessageCode messageEnumConstructorTearoff = const MessageCode(
     "EnumConstructorTearoff",
     problemMessage: r"""Enum constructors can't be torn off.""");
 
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<Message Function(String name)>
+    templateEnumContainsRestrictedInstanceDeclaration =
+    const Template<Message Function(String name)>(
+        problemMessageTemplate:
+            r"""An enum can't declare a non-abstract member named '#name'.""",
+        withArguments: _withArgumentsEnumContainsRestrictedInstanceDeclaration);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<Message Function(String name)>
+    codeEnumContainsRestrictedInstanceDeclaration =
+    const Code<Message Function(String name)>(
+  "EnumContainsRestrictedInstanceDeclaration",
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsEnumContainsRestrictedInstanceDeclaration(String name) {
+  if (name.isEmpty) throw 'No name provided';
+  name = demangleMixinApplicationName(name);
+  return new Message(codeEnumContainsRestrictedInstanceDeclaration,
+      problemMessage:
+          """An enum can't declare a non-abstract member named '${name}'.""",
+      arguments: {'name': name});
+}
+
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
 const Code<Null> codeEnumContainsValuesDeclaration =
     messageEnumContainsValuesDeclaration;
 
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
 const MessageCode messageEnumContainsValuesDeclaration = const MessageCode(
     "EnumContainsValuesDeclaration",
-    problemMessage:
-        r"""Enums can't contain declarations of members with the name 'values'.""");
+    problemMessage: r"""An enum can't declare a member named 'values'.""");
 
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
 const Code<Null> codeEnumDeclarationEmpty = messageEnumDeclarationEmpty;

pkg/front_end/lib/src/fasta/source/source_enum_builder.dart

@@ -36,6 +36,7 @@ import '../fasta_codes.dart'
         templateDuplicatedDeclaration,
         templateDuplicatedDeclarationCause,
         templateDuplicatedDeclarationSyntheticCause,
+        templateEnumContainsRestrictedInstanceDeclaration,
         templateEnumConstantSameNameAsEnclosing;
 
 import '../kernel/body_builder.dart';
@@ -271,6 +272,28 @@ class SourceEnumBuilder extends SourceClassBuilder {
           fileUri);
     }
 
+    for (String restrictedInstanceMemberName in const [
+      "index",
+      "hashCode",
+      "=="
+    ]) {
+      Builder? customIndexDeclaration =
+          scope.lookupLocalMember(restrictedInstanceMemberName, setter: false);
+      if (customIndexDeclaration is MemberBuilder &&
+          !customIndexDeclaration.isAbstract) {
+        // Retrieve the earliest declaration for error reporting.
+        while (customIndexDeclaration?.next != null) {
+          customIndexDeclaration = customIndexDeclaration?.next;
+        }
+        parent.addProblem(
+            templateEnumContainsRestrictedInstanceDeclaration
+                .withArguments(restrictedInstanceMemberName),
+            customIndexDeclaration!.charOffset,
+            customIndexDeclaration.fullNameForErrors.length,
+            fileUri);
+      }
+    }
+
     SourceFieldBuilder valuesBuilder = new SourceFieldBuilder(
         /* metadata = */ null,
         listType,

pkg/front_end/messages.status

@@ -217,6 +217,8 @@ EnumConstructorSuperInitializer/analyzerCode: Fail
 EnumConstructorSuperInitializer/example: Fail
 EnumConstructorTearoff/analyzerCode: Fail
 EnumConstructorTearoff/example: Fail
+EnumContainsRestrictedInstanceDeclaration/analyzerCode: Fail
+EnumContainsRestrictedInstanceDeclaration/example: Fail
 EnumContainsValuesDeclaration/analyzerCode: Fail
 EnumContainsValuesDeclaration/example: Fail
 EnumDeclaresConstFactory/analyzerCode: Fail
@@ -225,6 +227,8 @@ EnumDeclaresFactory/analyzerCode: Fail
 EnumDeclaresFactory/example: Fail
 EnumFactoryRedirectsToConstructor/analyzerCode: Fail
 EnumFactoryRedirectsToConstructor/example: Fail
+EnumImplementerContainsForbiddedInstanceDeclaration/analyzerCode: Fail
+EnumImplementerContainsForbiddedInstanceDeclaration/example: Fail
 EnumImplementerContainsValuesDeclaration/analyzerCode: Fail
 EnumImplementerContainsValuesDeclaration/example: Fail
 EnumInstantiation/example: Fail

pkg/front_end/messages.yaml

@@ -5493,7 +5493,7 @@ EnumFactoryRedirectsToConstructor:
   problemMessage: "Enum factory constructors can't redirect to generative constructors."
 
 EnumContainsValuesDeclaration:
-  problemMessage: "Enums can't contain declarations of members with the name 'values'."
+  problemMessage: "An enum can't declare a member named 'values'."
 
 EnumImplementerContainsValuesDeclaration:
   problemMessage: "'#name' has 'Enum' as a superinterface and can't contain non-static member with name 'values'."
@@ -5516,3 +5516,6 @@ NonAugmentationClassMemberConflictCause:
 
 OptionalSuperParameterWithoutInitializer:
   problemMessage: "Type '#type' of the optional super-initializer parameter '#name' doesn't allow 'null', but the parameter doesn't have a default value, and the default value can't be copied from the corresponding parameter of the super constructor."
+
+EnumContainsRestrictedInstanceDeclaration:
+  problemMessage: "An enum can't declare a non-abstract member named '#name'."

pkg/front_end/testcases/enhanced_enums/declared_equals.dart

@@ -0,0 +1,23 @@
+// Copyright (c) 2022, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+enum E1 {
+  element;
+
+  bool operator==(Object other) => true; // Error.
+}
+
+enum E2 {
+  element;
+
+  bool operator==(Object other); // Ok.
+}
+
+abstract class I3 {
+  bool operator==(Object other);
+}
+
+enum E3 implements I3 { element } // Ok.
+
+main() {}

pkg/front_end/testcases/enhanced_enums/declared_equals.dart.strong.expect

@@ -0,0 +1,68 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/enhanced_enums/declared_equals.dart:8:16: Error: An enum can't declare a non-abstract member named '=='.
+//   bool operator==(Object other) => true; // Error.
+//                ^^
+//
+import self as self;
+import "dart:core" as core;
+
+class E1 extends core::_Enum /*isEnum*/  {
+  static const field core::List<self::E1> values = #C4;
+  static const field self::E1 element = #C3;
+  const constructor •(core::int index, core::String name) → self::E1
+    : super core::_Enum::•(index, name)
+    ;
+  method toString() → core::String
+    return "E1.${this.{core::_Enum::_name}{core::String}}";
+  operator ==(core::Object other) → core::bool
+    return true;
+}
+class E2 extends core::_Enum /*isEnum*/  {
+  static const field core::List<self::E2> values = #C6;
+  static const field self::E2 element = #C5;
+  const constructor •(core::int index, core::String name) → self::E2
+    : super core::_Enum::•(index, name)
+    ;
+  method toString() → core::String
+    return "E2.${this.{core::_Enum::_name}{core::String}}";
+  abstract operator ==(core::Object other) → core::bool;
+}
+abstract class I3 extends core::Object {
+  synthetic constructor •() → self::I3
+    : super core::Object::•()
+    ;
+  abstract operator ==(core::Object other) → core::bool;
+}
+class E3 extends core::_Enum implements self::I3 /*isEnum*/  {
+  static const field core::List<self::E3> values = #C8;
+  static const field self::E3 element = #C7;
+  const constructor •(core::int index, core::String name) → self::E3
+    : super core::_Enum::•(index, name)
+    ;
+  method toString() → core::String
+    return "E3.${this.{core::_Enum::_name}{core::String}}";
+}
+static method main() → dynamic {}
+
+constants  {
+  #C1 = 0
+  #C2 = "element"
+  #C3 = self::E1 {index:#C1, _name:#C2}
+  #C4 = <self::E1>[#C3]
+  #C5 = self::E2 {index:#C1, _name:#C2}
+  #C6 = <self::E2>[#C5]
+  #C7 = self::E3 {index:#C1, _name:#C2}
+  #C8 = <self::E3>[#C7]
+}
+
+
+Constructor coverage from constants:
+org-dartlang-testcase:///declared_equals.dart:
+- E1. (from org-dartlang-testcase:///declared_equals.dart:5:6)
+- _Enum. (from org-dartlang-sdk:///sdk/lib/core/enum.dart:103:9)
+- Object. (from org-dartlang-sdk:///sdk/lib/core/object.dart:25:9)
+- E2. (from org-dartlang-testcase:///declared_equals.dart:11:6)
+- E3. (from org-dartlang-testcase:///declared_equals.dart:21:6)

pkg/front_end/testcases/enhanced_enums/declared_equals.dart.strong.transformed.expect

@@ -0,0 +1,68 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/enhanced_enums/declared_equals.dart:8:16: Error: An enum can't declare a non-abstract member named '=='.
+//   bool operator==(Object other) => true; // Error.
+//                ^^
+//
+import self as self;
+import "dart:core" as core;
+
+class E1 extends core::_Enum /*isEnum*/  {
+  static const field core::List<self::E1> values = #C4;
+  static const field self::E1 element = #C3;
+  const constructor •(core::int index, core::String name) → self::E1
+    : super core::_Enum::•(index, name)
+    ;
+  method toString() → core::String
+    return "E1.${this.{core::_Enum::_name}{core::String}}";
+  operator ==(core::Object other) → core::bool
+    return true;
+}
+class E2 extends core::_Enum /*isEnum*/  {
+  static const field core::List<self::E2> values = #C6;
+  static const field self::E2 element = #C5;
+  const constructor •(core::int index, core::String name) → self::E2
+    : super core::_Enum::•(index, name)
+    ;
+  method toString() → core::String
+    return "E2.${this.{core::_Enum::_name}{core::String}}";
+  abstract operator ==(core::Object other) → core::bool;
+}
+abstract class I3 extends core::Object {
+  synthetic constructor •() → self::I3
+    : super core::Object::•()
+    ;
+  abstract operator ==(core::Object other) → core::bool;
+}
+class E3 extends core::_Enum implements self::I3 /*isEnum*/  {
+  static const field core::List<self::E3> values = #C8;
+  static const field self::E3 element = #C7;
+  const constructor •(core::int index, core::String name) → self::E3
+    : super core::_Enum::•(index, name)
+    ;
+  method toString() → core::String
+    return "E3.${this.{core::_Enum::_name}{core::String}}";
+}
+static method main() → dynamic {}
+
+constants  {
+  #C1 = 0
+  #C2 = "element"
+  #C3 = self::E1 {index:#C1, _name:#C2}
+  #C4 = <self::E1>[#C3]
+  #C5 = self::E2 {index:#C1, _name:#C2}
+  #C6 = <self::E2>[#C5]
+  #C7 = self::E3 {index:#C1, _name:#C2}
+  #C8 = <self::E3>[#C7]
+}
+
+
+Constructor coverage from constants:
+org-dartlang-testcase:///declared_equals.dart:
+- E1. (from org-dartlang-testcase:///declared_equals.dart:5:6)
+- _Enum. (from org-dartlang-sdk:///sdk/lib/core/enum.dart:103:9)
+- Object. (from org-dartlang-sdk:///sdk/lib/core/object.dart:25:9)
+- E2. (from org-dartlang-testcase:///declared_equals.dart:11:6)
+- E3. (from org-dartlang-testcase:///declared_equals.dart:21:6)

pkg/front_end/testcases/enhanced_enums/declared_equals.dart.textual_outline.expect

@@ -0,0 +1,19 @@
+enum E1 {
+  element;
+
+  bool operator ==(Object other) => true;
+}
+
+enum E2 {
+  element;
+
+  bool operator ==(Object other);
+}
+
+abstract class I3 {
+  bool operator ==(Object other);
+}
+
+enum E3 implements I3 { element }
+
+main() {}

pkg/front_end/testcases/enhanced_enums/declared_equals.dart.textual_outline_modelled.expect

@@ -0,0 +1,19 @@
+abstract class I3 {
+  bool operator ==(Object other);
+}
+
+enum E1 {
+  element;
+
+  bool operator ==(Object other) => true;
+}
+
+enum E2 {
+  element;
+
+  bool operator ==(Object other);
+}
+
+enum E3 implements I3 { element }
+
+main() {}

pkg/front_end/testcases/enhanced_enums/declared_equals.dart.weak.expect

@@ -0,0 +1,68 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/enhanced_enums/declared_equals.dart:8:16: Error: An enum can't declare a non-abstract member named '=='.
+//   bool operator==(Object other) => true; // Error.
+//                ^^
+//
+import self as self;
+import "dart:core" as core;
+
+class E1 extends core::_Enum /*isEnum*/  {
+  static const field core::List<self::E1> values = #C4;
+  static const field self::E1 element = #C3;
+  const constructor •(core::int index, core::String name) → self::E1
+    : super core::_Enum::•(index, name)
+    ;
+  method toString() → core::String
+    return "E1.${this.{core::_Enum::_name}{core::String}}";
+  operator ==(core::Object other) → core::bool
+    return true;
+}
+class E2 extends core::_Enum /*isEnum*/  {
+  static const field core::List<self::E2> values = #C6;
+  static const field self::E2 element = #C5;
+  const constructor •(core::int index, core::String name) → self::E2
+    : super core::_Enum::•(index, name)
+    ;
+  method toString() → core::String
+    return "E2.${this.{core::_Enum::_name}{core::String}}";
+  abstract operator ==(core::Object other) → core::bool;
+}
+abstract class I3 extends core::Object {
+  synthetic constructor •() → self::I3
+    : super core::Object::•()
+    ;
+  abstract operator ==(core::Object other) → core::bool;
+}
+class E3 extends core::_Enum implements self::I3 /*isEnum*/  {
+  static const field core::List<self::E3> values = #C8;
+  static const field self::E3 element = #C7;
+  const constructor •(core::int index, core::String name) → self::E3
+    : super core::_Enum::•(index, name)
+    ;
+  method toString() → core::String
+    return "E3.${this.{core::_Enum::_name}{core::String}}";
+}
+static method main() → dynamic {}
+
+constants  {
+  #C1 = 0
+  #C2 = "element"
+  #C3 = self::E1 {index:#C1, _name:#C2}
+  #C4 = <self::E1*>[#C3]
+  #C5 = self::E2 {index:#C1, _name:#C2}
+  #C6 = <self::E2*>[#C5]
+  #C7 = self::E3 {index:#C1, _name:#C2}
+  #C8 = <self::E3*>[#C7]
+}
+
+
+Constructor coverage from constants:
+org-dartlang-testcase:///declared_equals.dart:
+- E1. (from org-dartlang-testcase:///declared_equals.dart:5:6)
+- _Enum. (from org-dartlang-sdk:///sdk/lib/core/enum.dart:103:9)
+- Object. (from org-dartlang-sdk:///sdk/lib/core/object.dart:25:9)
+- E2. (from org-dartlang-testcase:///declared_equals.dart:11:6)
+- E3. (from org-dartlang-testcase:///declared_equals.dart:21:6)